The invention relates to a method and an assembly for removing a device from a wall box for a large-scale combustion device. The wall box is located within a wall port of the combustion device in order to receive the device, such as a cleaning device or an imaging device.
During the operation of large-scale combustion devices, such as boilers that burn fossil fuels, slag and ash encrustations develop on interior surfaces of the boiler. The presence of these deposits degrades the thermal efficiency of the boiler. Therefore, it is periodically necessary to remove such encrustations. Various removable cleaning devices are currently used to remove these encrustations.
One such type of removable cleaning device includes a device referred to as a “sootblower”. Sootblowers are used to project a stream of cleaning fluid, such as air, steam or water, into the interior volume of the boiler. In the case of long retracting type sootblowers, a lance tube is periodically advanced into and withdrawn from the boiler. As the lance tube is advanced into and withdrawn from the boiler, it rotates or oscillates in order to direct one or more jets of cleaning fluid at desired surfaces within the boiler. In the case of stationary sootblowers, the lance tube is maintained within the boiler during periods of use and during periods of non-use. Sootblower lance tubes project through openings in the boiler wall, referred to as wall ports. The wall ports may include a mounting assembly, such as a wall box, in order to properly position the lance tube with respect to the boiler wall.
Retracting sootblowers are typically partially or completely removed from the wall box when not in use. Therefore, retracting sootblowers are frequently inserted to and removed from the boiler interior volume. Although stationary sootblowers are typically maintained within the boiler interior volume, they may need to be removed from the boiler for servicing the sootblower or for other various purposes. Therefore, retracting sootblowers and stationary sootblowers are both considered to be removable cleaning devices.
Another such type of removable cleaning device is commonly referred to as a “water cannon”. Water cannons involve the use of a monitor or nozzle positioned within a wall port in order to eject a stream of fluid, such as water, into the interior volume of the combustion device. The water cannon nozzle typically includes a pivot joint to permit adjustment of the direction of the stream of fluid. Similarly to the sootblower, the water cannon nozzle is positioned within the wall port via a mounting assembly, such as a wall box. Unlike the sootblower, however, the water cannon nozzle preferably includes a pivotable ball joint coupled with the wall box in order to adjust the direction of the stream of fluid flowing into the boiler interior volume. Due to the presence of the pivotable ball joint, the wall port for a water cannon assembly is typically larger than the wall port for a sootblower.
Similarly to the stationary sootblower, the water cannon nozzle is typically maintained within the boiler during periods of use and during periods of non-use. However, water cannon assemblies may need to be removed from the boiler for servicing the water cannon or for other various purposes. Therefore, water cannon assemblies are also considered to be removable cleaning devices.
Other removable devices, besides cleaning devices, may penetrate the boiler wall via a wall port in order to perform a desired function. One such device is an imaging device, such as an infrared imaging device. Imaging devices are often used to examine the interior volume and the interior surfaces of the boiler in order to check the boiler status or to perform maintenance on the boiler. Similarly to the cleaning devices, the imaging device typically penetrates a wall port in order to view the boiler interior volume. The imaging device may be extended into the boiler interior volume similarly to a sootblower lance, it may be coupled with a pivoting ball joint similarly to a water cannon assembly, or it may be used in any other appropriate configuration. Regardless of the configuration of the imaging device, it typically includes a mounting assembly located within the boiler wall port.
Depending on the configuration of the imaging device, it may be typically maintained within the boiler during periods of use and during periods of non-use, or it may typically be removed from the boiler during periods of non-use. Regardless of the typical configuration of the imaging device with respect to the boiler, the imaging device may need to be removed from the boiler for servicing the device or for other various purposes. Therefore, imaging devices are considered to be removable cleaning devices regardless of their typical configuration with respect to the boiler.
Boiler gases may pose various health risks and dangers, such as including toxic or otherwise dangerous compositions. Therefore, it is advantageous to include substantially fluid-tight seal(s) between various components of the wall box and of the removable device.
Furthermore, boiler gases typically reach extremely high temperatures. Therefore, it is advantageous to include heat-resistant seal(s) between various components of the wall box and of the removable device in order to protect the boiler users from the boiler temperatures and in order to minimize fire hazards. The fluid-tight seals and the heat-resistant seals may be the same seals performing multiple functions.
Positive-pressure boilers operate with an internal pressure higher than the ambient pressure some boilers. Therefore, due to the internal pressure of positive-pressure boilers, it may be especially difficult to maintain the substantially seals and prevent boiler gases from escaping during removal of the removable device from a positive-pressure boiler.
Other types of boilers, such as ambient-pressure boilers and negative-pressure boilers, also may experience undesirable gas exchange with the ambient air if preventative measures are not taken. Similarly, the heat of the boiler gas may pose health and fire hazards regardless of the pressure differential between the boiler interior and the ambient air. Therefore, it is desirable to maintain the seals during removal of the removable device in all types of boilers.
As seen from above, it is desirous to provide an improved system and an improved method for protecting boiler users, minimizing fire hazards, and substantially preventing fluid exchange between the boiler and the ambient air during removal of various removable devices from the boiler wall box.